If you're 62 years or older, you can save at least 15 percent on your room rate or take advantage of our Senior Stay for Breakfast package! (marriott.com)
Check out their bed and breakfast package if you are looking for the most bang for your buck. (ordinarytraveler.com)
I suspect the discount will apply to the «best available rate» so that should include the prepaid rate but will not necessarily include things like breakfast packages. (travelingformiles.com)